Capri Holdings (CPRI), the parent company of Michael Kors and Jimmy Choo, saw shares plunge around 47% in early trading on Friday after a US judge blocked its pending $8.5 billion acquisition by Coach owner Tapestry (TPR).

In a court filing obtained by Yahoo Finance, US District Judge Jennifer Rochon ruled that "antitrust has come into fashion," arguing a merger between the two fashion powerhouses "will substantially lessen competition in the market for accessible-luxury handbags."

Tapestry and Capri announced the proposed tie-up last year. The combination would have brought together six high-profile fashion brands under one roof: Tapestry’s Coach, Stuart Weitzman, and Kate Spade with Capri’s Versace, Jimmy Choo, and Michael Kors.

Tapestry stock moved in the opposite direction of Capri in the aftermath of the late-Thursday news, rising roughly 14% in early morning trading Friday.

In a statement released Thursday evening, Tapestry said it plans to appeal the decision, adding, "Tapestry and Capri operate in an industry that is intensely competitive and dynamic, constantly expanding, and highly fragmented among both established players and new entrants.

"We face competitive pressures from both lower- and higher-priced products and continue to believe this transaction is pro-competitive and pro-consumer."

The Federal Trade Commission had moved to block the acquisition in April, seeking a preliminary injunction to stop the deal. That injunction was granted by Rochon on Thursday.

At the time, the agency had argued the acquisition would "[threaten] to deprive consumers of the competition for affordable handbags, while hourly workers stand to lose the benefits of higher wages and more favorable workplace conditions."

Tapestry fought back against those claims, arguing a merger was necessary in order to compete against dominant European players like Gucci.

The ruling blocks the deal while the FTC goes forward with its proceedings, but all parties will still have the chance to argue their case before the FTC.

"Today’s decision is a victory not only for the FTC, but also for consumers across the country seeking access to quality handbags at affordable prices," Henry Liu, director of the FTC’s Bureau of Competition, said in a statement. "These bags are a product which millions of people rely on throughout their daily lives. The decision will ensure that Tapestry and Capri continue to engage in head-to-head competition to the benefit of the American public."

Prior to Thursday's ruling, Pauline Brown, former North American chair at LVMH, which owns fashion brands like Louis Vuitton and Dior, told Yahoo Finance the FTC would face a "high hurdle" in making its case.